1. Field of the Invention
The present invention relates to an image processing apparatus and a control method thereof.
2. Description of the Related Art
Recently various color correction methods (color conversion methods) to match color reproducibility between different media, such as between a display apparatus and paper, or between a display apparatus and a projector, have been proposed. A method of matching color reproducibility between different media is disclosed, for example, in Japanese Patent Application Laid-open No. H6-333001. In concrete terms, Japanese Patent Application Laid-open No. H6-333001 discloses a method of performing color correction processing on image data to be displayed on a display apparatus or image data to be printed by a printer, so that the XYZ tristimulus values of the colors of the image displayed on the display apparatus and the XYZ tristimulus values of the colors printed by the printer match. Here the XYZ tristimulus values are the standard colors specified by CIE (Commission Internationale de l'Eclairage) that do not depend on a specific medium (e.g. colors that do not depend on a display apparatus). Specifically, the XYZ tristimulus values are psychophysical quantities derived by using the spectral distribution of light that enters the eyes and a color matching function that indicates the visual sensitivity of a person (virtual person) having standard visual characteristics (hereafter called “standard color matching functions”).
However visual characteristics differ depending on the person because of such causes the yellowing of the lens of the eyes due to aging and the person difference of photoreceptor cell characteristics. Therefore when an object is observed, different colors may be recognized depending on the person (observer). Further, when two objects having different spectral characteristics are observed, some observers may recognize the colors of objects as different, even if the XYZ tristimulus values of the two objects are the same. For example, the spectral characteristics are completely different between a display apparatus and paper. Therefore even if color correction processing is performed on image data to be displayed on a display apparatus such that an image with colors having the same XYZ tristimulus values as the colors of the image printed on paper is displayed, some observers may recognize a difference in the colors of the displayed image and the colors of the printed image. This phenomena (difference in color appearance depending on the person) is called “observer metamerism”.
A technique to control the difference in color appearance of an image due to the difference of the visual characteristics is disclosed, for example, in Japanese Patent Application Laid-open Nos. 2005-109583 and 2009-89364. Specifically, Japanese Patent Application Laid-open Nos. 2005-109583 and 2009-89364 disclose a display apparatus that stores a personal profile of each person, generated by color matching experiments, and displays the image data after performing color correction processing using a personal profile of a person who is an observer. The personal profile is correction data that indicates the visual characteristics of a corresponding person.